1. Field of the Invention
This invention pertains to a system for adjustably reducing the effective width of a slide for a gravity-fed machine intended for sorting a high volume of product.
2. Description of the Related Art
A typical sorting machine of the type using the present invention may generally be characterized as a gravity-fed sorter. A gravity-fed sorter incorporates at least one slide or chute positioned at a steep angle that may have one or more channels across the width of each slide. A hopper or other feed system is positioned to dispense product to the top of the slide or slides. Typically a near-horizontal surface, a tray, exists between the hopper, or feed system, and each slide. Some system, such as a vibratory feeder, may be associated with this tray to encourage product to flow from the hopper to the slide. If sorting with multiple channels is desired, the slide is divided across its width into channels to provide a uniform number of dispensed products to each channel. Techniques for distributing the proper amount of product to each channel of the slide are well-known in the art. When divided a slide may have any number of channels, limited only by the width of the slide and the channel width necessary to permit the desired product to pass.
In operation, each slide of these sorters presents a single-layer stream of product approaching distribution across the full width of the slide to the sorting machine's viewer system, which may view one or opposite sides of the passing product. The viewer system images the entire width of the passing product stream at a location referred to as the scan line to permit identification of the horizontal position of a particular product to be removed from the passing flow. Located below the viewer system is an ejector system that may include one or more rows of ejectors permitting removal of the selected product from the passing flow. As is known in the art, activation of the individual ejector or group of ejectors associated with the last known horizontal position of the product to be removed is delayed for a time period equal to that necessary for the product to be removed to pass from the scan line to the ejector. The individual ejector or group of ejectors activated thereby deflects the selected product from the stream of product. As can be appreciated for the effectiveness of the viewer, it is critical for each product to pass through the scan line and to do so visible to all viewers employed. Likewise as can be appreciated for the effectiveness of the ejector system, it is critical that each product to not to move laterally between the viewer and ejector system. Finally, it is also critical for the effectiveness of both components that each product follow a common trajectory.
Thus it is the purpose of the slide to accelerate and singulate the product flow so that each product has the same downward velocity and no lateral velocity, i.e. the same trajectory, and to present the product uniformly to the scan line. One manner of encouraging singulation is to pass product down the slide in sufficient volume to fill the slide to at least a minimum density. However, if product is supplied at less than the operating capacity of the single channel slide, then singulation may not be reached and product may travel laterally between the scan line and ejector system. Additionally, when product is not laterally constrained, either by full chute capacity or by channels, a smooth chute will not achieve singulation due to the lateral movement of the product. Thus a further manner of encouraging singulation is by locating multiple channels across the surface of the slide so that once product enters a channel, its lateral travel is reduced or eliminated. However, even if singulation is reached, a channeled chute will not operate at its highest efficiency if the slide is not run at capacity as substantial gaps will occur among products passing or in a flow to pass the scan line.
Often a flow rate is desired that is lower than that provided by the original slide. A lower flow rate may be desired for machine testing or for sorting of a volume of product below the flow rate optimal for the slide in the sorting machine, particularly in connection with small product volumes such as testing or new seed development. Logically, singulation may be achieved for such lower flow rates by reducing the width of the slide, thus increasing the density of the product. In the prior art, reducing the slide width has required removal of the original slide and installation of a slide having a width sized to or near to the desired flow rate. Thus changing slides has required the physical disassembly of the sorting machine. Moreover, as the width of the slide controls the flow rate, operators have been able to select from a limited number of flow rates absent a wide variety of slides.
By eliminating the need for disassembly and reassembly, and the time associated with the reconfiguration, the sorting machine may be made more productive. Likewise, by providing a greater number of potential flow rates, the sorting machine may be made more productive. However, merely changing the slide width would create further difficulties. The product is supplied to the tray at a flow rate consistent with the slide supplied with the sorting machine. Thus the flow rate of product to the tray must also be reduced to avoid overfilling the slide. Moreover, as the tray is sized with a width equal to the slide, the effective width of the tray must be reduced to avoid loss of product beyond the slide width or the need to recycle unprocessed product.
Thus there exists a need for a process and apparatus for rapidly reconfiguring the slide of a gravity slide sorter to various widths, for ensuring product is supplied only to the operable width of the slide sorter, and for reducing the flow rate from the product supply to the maximum capacity of the reduced slide width.